If you haven't yet specified your app's SHA-1 fingerprint, do so from the
Settings page
of the Firebase console. Refer to
Authenticating Your Client
for details on how to get your app's SHA-1 fingerprint.

If the call to signInWithCredential succeeds you can use the getCurrentUser method to get the user's account data.

Next steps

After a user signs in for the first time, a new user account is created and
linked to the credentials—that is, the user name and password, phone
number, or auth provider information—the user signed in with. This new
account is stored as part of your Firebase project, and can be used to identify
a user across every app in your project, regardless of how the user signs in.